Most Women Get Wrong Drug for Urinary Tract Infections

Study: Doctors favor pricey drugs over cheaper, first-line one

MONDAY, Jan. 14, 2002 (HealthDayNews) -- If you're a woman taking antibiotics for a urinary tract infection, chances are you're not on the drug that experts say you should be using.

A new study says three in four women don't receive Bactrim, the recommended front-line medication to control urinary tract infections (UTIs), which are a common bacterial ailment that affects millions of American women each year.

Although the other prescriptions aren't likely to affect patient care in the short run, the researchers say their use could promote drug resistance that may make UTIs much harder to treat in the future.

"Doctors make decisions on antibiotic use right then and there" for individual patients, says Dr. Elbert Huang, a University of Chicago researcher who was co-author of the study. "Their choice may be right for that person, but for society as a whole, it may be the wrong choice."

What's more, adds Huang, whose study appears in today's Archives of Internal Medicine, the first choice drug also happens to be the cheapest therapy. By ordering more expensive treatments, doctors are needlessly driving up health care costs. A recent study by government researchers showed that prescription drug spending rose by more than 17 percent in 2000, to almost $122 billion.

In 1999, the Infectious Disease Society of America set guidelines on the best way to treat uncomplicated urinary tract infections in women. The guidelines came from a 1993 paper the society published. According to the policies, doctors should first prescribe a drug called trimethoprim-sulphamethoxazole, or Bactrim. As a second line of defense, certain members of the potent but much more expensive fluoroquinolone class, which includes Cipro, can be used.

But Huang and his colleagues found that doctors are increasingly eschewing Bactrim for fluoroquinolones and even a third-tier drug called nitrofurantoin.

The researchers examined almost 1,500 outpatient visits for UTIs and bladder infections between 1989 and 1998. In the first year of the study, 48 percent of prescriptions were for trimethoprim; by 1998, those prescriptions had dropped by half. In the same time frame, the orders for fluoroquinolones prescriptions jumped from 19 percent to 29 percent, while those for nitrofurantoin rose from 14 percent to 30 percent.

What drug a woman received depended largely on the kind of doctor she saw. Internists, for example, were more likely to adhere to the infectious disease guidelines. But obstetricians and gynecologists favored nitrofurantoin over Bactrim and fluoroquinolones, which have been linked to birth defects.

Huang considers that preference "legitimate," and acknowledges that some of the choices likely considered other important factors like patient medication allergies. Yet he and his colleagues suspect that most of the reason doctors haven't followed the guidelines involves drug company marketing and promotion practices, not which pill works best. "Over the decade that we watched, there was really no change in terms of new trials showing that fluoroquinolones were better than Bactrim," he says.

Dr. Randall Stafford, a Stanford University researcher and co-author of the study, says many doctors choose broadly acting antibiotics for UTIs because they're looking for the biggest fly swatter available. "Some physicians prefer to use an antibiotic that's going to work no matter what," Stafford says. Yet some of the impetus for ordering heavyweight compounds also comes from patients, he says.

While urinary tract bacteria might not notice the difference between Bactrim and Cipro, the health care system certainly does. The first compound costs less than $2 for a 10-day supply, compared with as much as $70 for the same amount of Cipro. Generic nitrofurantoin falls in between, at about $20 for the 10-day regimen.

In other words, with 2.45 million prescriptions written annually for UTIs, the decision not to use Bactrim as the first-line therapy for UTIs can cost patients or health insurers tens of millions of dollars in unnecessary charges, the researchers say.

If that's not a sufficient deterrent to follow the infection society's recommendations, Huang says failure to do so may ultimately make treating UTIs far more difficult. Spreading the burden of killing the disease-causing bacteria over several drugs promotes resistance to each of them concurrently.

A better approach, and the one experts advise, is to use a single drug -- in this case Bactrim -- until it works no more. "The idea is that we push the envelope as far as we can with a single agent, thus preserving the efficacy of other drugs," he says.

Dr. James R. Johnson, a University of Minnesota physician who helped write the 1999 UTI treatment guidelines, says bugs resistant to Bactrim and its near relatives have become more common. So the increase in prescriptions for other drugs isn't necessarily concerning. On the other hand, he adds, "it would be a mistake" if doctors were offering their patients stronger medications without knowing they were infected with resistant organisms.

Johnson considers the surge in fluoroquinolone use particularly alarming, since losing these drugs to resistance would be a major setback for infection control in general. As a result, he says, it's probably wiser to use nitrofurantoin as the runner-up to Bactrim for urinary infections.

What To Do

To find out more about urinary tract infections, try the National Institute of Diabetes and Digestive and Kidney Diseases or MEDLINEplus.

You can also visit the UrologyChannel.

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